Batch atomic operation support
Not sure if that's applicable to Membase since it would require changes to the Memcached code base, but it would be very useful for us to have a 'increments' method incrementing multiple keys at once.
Here's our use case. We've got a log processing application using Memcached as a distributed counter. One log entry generates approximately 500 increments. Because these need to be executed individually, network latency is creating a bottleneck. All other operations are run in parallel. I expect that a batch-increment feature would increase log processing speed by a factor of 2 or 3x, from 500ms to about 150ms.
I could also see the use of batch modes for all standard memcached operations - store, remove, append, prepend, increment, decrement.